The use of retaining walls to protect and beatify property in all types of environmental settings is a common practice in the landscaping, construction and environmental protection fields. Walls constructed from various materials are used to outline sections of property for particular uses, such as gardens or flower beds, fencing in property lines, reduction of erosion, and to simply beautify areas of a property.
Numerous methods and materials exist for the construction of retaining walls. Such methods include the use of natural stone, poured in place concrete, masonry, landscape timbers or railroad ties. In recent years, segmental concrete retaining wall units, sometimes known as keystones, which are dry stacked (i.e., built without the use of mortar), have become a widely accepted product for the construction of retaining walls. Examples of such units are described in U.S. Pat. No. RE 34,314 (Forsberg) and in U.S. Pat. No. 5,294,216 (Sievert).
However, many of the materials utilized in the construction of retaining walls are susceptible to deterioration and/or are not very aesthetically appealing. The ability of these retaining walls to withstand sunlight, wind, water, general erosion and other environmental elements is a problem with most retaining wall products.
A particular concern is the utilization of erosion protection materials in water shorelines. Leaving the shoreline natural can lead to erosion, cause an unmanageable and unusable shoreline, create high maintenance, and inhibit an aesthetically pleasing property. Many materials utilized in retention of shorelines are subject to immediate deterioration and/or are not as aesthetically appealing as one would desire. Furthermore, many materials utilized on shoreline structures are difficult to maintain due to the awkward location in the water and also the prevalent growth and presence of organic materials that can get caught and flourish in such a structure. For example, many lakeshore or ocean side properties utilize riprap as a retention device for prevention of erosion. Riprap is a configuration of large to medium size stones placed along the shoreline. A problem with waterfront properties that use a continuous wall of typical riprap is the shoreline will retain some organic material or will accumulate additional organic material brought in by the water. This usually leads to an unmanageable and aesthetically displeasing shoreline or higher maintenance. Furthermore, the riprap is never uniform in color and size and therefore does not as provide the most aesthetically pleasing shoreline or complete coverage of the shoreline. The lack of uniform shoreline coverage allows for some erosion, collection of various materials and the growth of weeds.
Another problem with materials normally utilized in the construction of retaining walls, such as poured in place concrete, masonry, landscape timbers, railroad ties or keystones is that regulations in most states and counties prohibit their use in or near bodies of water because of the crumbling or deterioration of the material into the body of water over time or the leaching of chemicals from the materials into the body of water. Many of these retaining wall materials dissolve, crumble, break apart and/or float into the body of water for which they line causing problems with the shoreline and pollution of the water. For example, the average life of various types of concrete block or keystone in water is approximately a couple of years. A need exists for a retaining wall, which would be resistant to such deterioration.
An additional concern that exists in the construction of retaining walls is the weight of the materials. Concrete blocks, large or medium size stones, timbers or keystones can be heavy and cumbersome to move into the wall location and maneuver when constructing the wall. Many locations for which retaining walls are constructed are positioned in awkward terrain. Heavy building materials are difficult to move into the location and furthermore are difficult to position when constructing the retaining wall thereby adding additional cost and labor for installation. However, the heavy materials are needed once the wall is constructed to provide stability and security to the structure. Therefore, the easy to install light-weight units used for the construction of a retaining wall, which can be weighted once placed into position thus retaining the block in position and stabilizing the completed retaining wall, would be beneficial to construction of such structures.